#define GPIOA_MODER    *(unsigned  int *)(0x40020000UL)
#define GPIOA_ODR      *(unsigned  int *)(0x40020014UL)
#define RCC_AHB1ENR    *(unsigned  int *)(0x40023830UL)
int main(void)
{
	unsigned int delay = 1000000;
	RCC_AHB1ENR |= 1 << 0;
	GPIOA_MODER |= 1 <<(5*2);
	while(1)
	{
		GPIOA_ODR |= 1 << 5;
		delay = 1000000;
		while(delay--);
		GPIOA_ODR &= ~((unsigned int)(1<<5));
		delay = 1000000;
		while(delay--);
	}
}
